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Thursday, December 29, 2011

Science of Sport Awards: Controversy of the year, Oscar Pistorius

2011 Awards: Controversy of the year - Pistorius, go-karts and Formula 1 machines

Controversy is never far from sport, and therefore the science of sport.  Many of the controversies in recent years have been directly related to science - think Caster Semenya in 2009, doping in sport (every year), swimsuits and performance in 2008.

2011 didn't produce a "new" controversy, but rather reruns of the same dramas we've discussed before.  However, one of those was comfortably, for this site anyway, the most relevant and debated story in sports science, and it was the case of Oscar Pistorius, the Controversy of 2011.

Pistorius - the scientific evidence and the PR machine

So much has been written on this topic that I won't devote an entire post to explaining the science...again.  I am sure every one of you knows the story - a South African double-amputee, bursts onto the scene in 2004, declares an intention to run in the Olympic Games in 2007, then goes through two rounds of scientific testing to confirm his claims that the high-tech carbon fiber blades that he runs with (called Cheetahs) do not give him a performance advantage.  

Those two rounds of testing are done first at the request of the IAAF in Germany, and then in Texas as part of Pistorius' appeal against the ban issued based on the results from the Germany tests.  

But what did the tests show?  Somewhere along the journey, the science is hijacked by a massive PR machine that has followed Pistorius since 2007, and which applies pressure to the IAAF to permit his participation, and then ultimately on the process by which the Court of Arbitration ultimately declared that there was insufficient evidence to ban Pistorius.

2011 then was not the year that the Pistorius question was first asked.  Rather, it was the year that it became relevant, for Pistorius qualified for the IAAF World Championships and raced in Daegu in August.  That created a firestorm of media coverage, and the resultant question was asked.  The same will likely be true in 2012, and so this is an issue that will almost certainly be revisited then.

But these are the crucial facts, most of which have been overlooked by the media, or obscured by lies and PR tactics.

The scientific explanation - back to theory, proven by tests

The two rounds of testing revealed fairly conclusively that Pistorius did not "run" in the manner that able-bodied runners do.  Mechanically, it was a totally different locomotion, which Peter Bruggemann, the German biomechanist who did the German testing, described as a "bouncing locomotion at a lower metabolic cost".

The "metabolic cost" statement was important, and was made based on tests that showed that Pistorius used 25% less oxygen during 400m sprinting than able-bodied runners.  That by itself is not a performance advantage, but it is very important when you keep in mind the entire scientific process.  That process must begin with a question and scientific rationale.  That question is "Does Pistorius enjoy a performance advantage?" and the rationale is:
  • More energy return from carbon fiber than human tendon means that metabolic cost would be reduced.  That's important because the ability to run at a given pace for 400m is limited by metabolic changes in the muscle.  These can't be measured directly, but metabolic cost is a proxy for them
  • Lighter mass of carbon fiber limbs means lower cost of accelerating the limbs, allowing quicker limb movement and therefore sprinting
  • Carbon fiber does not fatigue, whereas muscle/tendon is known to be significantly affected by the end of a 400m race
So the metabolic finding by Bruggemann confirmed the first 2 points above.  Directly, using less oxygen has little bearing on sprint performance, but it does point to confirmation of energy return, metabolic and performance advantages. On the note of the energy return, Bruggemann measured energy loss in the human tendon at 41%, compared to only 8% for the carbon fiber blade, so the picture came together pretty clearly.  Hence the ban.  You can read more about the German-testing at this detailed piece I wrote in August

However, there were problems with the research, particularly the measurement of oxygen during sprinting.  There's no doubt the conclusion was made too broadly based on the tests, a mistake that would prove costly in the scientific "debate" at CAS, because it gave Pistorius a fairly easy means to refute the finding.  

That is, Pistorius was able to appeal the decision and perform his own tests, and his team designed a test that would measure oxygen use during slower, low-intensity running.  

Those tests again showed that Pistorius used less oxygen than able-bodied runners, even when running slowly (17% lower, to be precise).  However, by "creatively" adding in data from world class distance runners measured over a period of ten years, the researchers were able to manipulate the data sufficiently to show that he was not statistically different from other runners.  The fact that these runners were not sprinters, but marathon runners, seemed not to matter to either the scientists, or CAS, or the media who have covered the story.  

It's an extra-ordinary comparison to make, particularly when you consider that data do exist for other sprinters.  And most tellingly, when you compare Pistorius to these other sprinters, then suddenly you get a picture that shows that he is 14% and 2.3 SD more economical.  That's a big difference, and had they included those comparisons, as they should have, then the conclusion of the "scientific" paper would have been totally different - it would have had to conclude that Pistorius is metabolically and mechanically different from able-bodied runners, and these differences are consistent with a performance advantage.

The "missing evidence" - never presented at CAS

Then the story got even more remarkable.  Having cleared Pistorius to compete, a research article was published by a team of six scientists.  This is the research described above, where Pistorius was found to be metabolically similar to distance runners.  This is the foundation of the data presented to the CAS.

But 18 months later, an extra-ordinary announcement followed.  It was made by Peter Weyand and Matthew Bundle, TWO of the group of six scientists in the Pistorius research team.  They came out in November 2009 with the statement that "Pistorius enjoys a large advantage", and that "we knew it all along".

This remarkable statement was followed by a point-counterpoint debate in the Journal of Applied Physiology, which revealed a split among those six scientists.  It transpired that on the very first day of testing, Weyand (the world's leading authority on sprint mechanics) and Bundle noted that Pistorius' mechanics were "off the charts".  Specifically, his lighter carbon fiber prosthetic blades enabled him to accelerate his limbs so rapidly that he could do what no other runner could in terms of repositioning his limbs.  

Weyand had previously established that a limit to sprinting, regardless of speed, was the ability to reposition the limbs, and Pistorius "broke" the limit considerably.  That led Weyand to recognize the performance advantage.  Weyand and Bundle describe this in their own words: 
"Reduced limb repositioning times allow Mr. Pistorius to spend less time in the air between steps.  Shorter aerial periods, in turn, substantially reduce how hard Mr. Pistorius must hit the ground during each stance period to lift and move his body forward into the next step.
In this sense, the level of sprinting athleticism required for Mr. Pistorius to achieve world class speeds is dramatically reduced compared to his intact limb competitors.  Mr. Pistorius attains world-class sprinting speeds with the ground forces and foot-ground contact times of a slow and relatively uncompetitive runner.  Mr. Pistorius’ intact-limb competitors, with natural limb weights and swing times, lack this option, and therefore must achieve their speeds via exclusively biological means.  Mr. Pistorius, in contrast, achieves these speeds through the use of technology"
You can read more about this discovery and the basis for the 12-second advantage they calculated (an overestimate in my opinion) in the detailed article on this site written in August.

Weyand and Bundle speak

The above statements come from a piece that was written by Weyand and Bundle in response to articles I wrote on this site in August.  They contacted me to request a one-time post on The Science of Sport, and I was very happy to oblige.  However, for various reasons, the posts didn't happen here, but they were published on the SMU website.  I would highly encourage you to read them - they are lucid, to the point, and they clear up many of the misconceptions that you'd have read in the popular media as a result of lies told by Pistorius, Hugh Herr and co.
The CAS hearing: Evidence not presented, the cover-up of omission

I got the distinct impression that Weyand and Bundle wanted to speak because they had not been given the opportunity to do so, until these posts.

What emerges is the even more remarkable fact that when it came time to present the science to the Court of Arbitration for Sport, the Weyand-Bundle finding on the advantage was NOT even presented.  Neither Weyand nor Bundle even attended the hearing.

In other words, having identified on the very first day that there was an advantage ("we knew all along"), Weyand and Bundle did not have the opportunity to present what they knew, and their colleagues who represented them deemed it unnecessary to present this evidence.

The end result is that the judges at CAS made a decision based on half the scientific evidence (evidence which was, as I've described, flawed to begin with as a result of those creative comparisons), and completely overlooked the half that suggests the advantage.

It was, quite simply, a cover-up of omission.  How can the search for scientific truth be punctuated by:
  1. Failure to make the correct comparison between a sprinter and another sprinter, but rather to include data from other research on distance runners?  This only obscures the truth, by creating a false similarity
  2. Failure to even disclose the evidence that suggests, based on all that we know about the theory of sprinting performance, that the athlete in question has a large performance advantage?
For these reasons, this case should be kept alive, and the media, who have been astonishingly passive in trying to pursue the story, should be roused into answering these questions.  At the very least, the CAS should take heed of the fact that they had a hearing where evidence was not discussed in an objective manner, and their decision is thus an ignorant one.

The end result of this is that Pistorius was "cleared", based not on science, but on a legal process that was manipulated by science and the huge drive to permit Pistorius to run.  And make no mistake, there is inspiration in the story.

In fact, it got to the point where despite the science, I can appreciate the viewpoint of those who say "Sure, there is an advantage, but there's only one such athlete, and he's not running away with the gold medals, and so the good outweighs the bad, so let him compete despite that advantage".

I disagree with that, but I can respect the opinion of those who believe it.  What cannot be accepted, however, is the assertion that there is no advantage.  Everything about the science points to the advantage, from the pacing strategy he uses, to the German-testing that found mechanical and metabolic differences, to the Texas testing which provided evidence of an athletic advantage.

The science was clear, from the point of hypothesis, to the theory behind it, to the evidence.  The deceit in the case, fueled by a willfully ignorant media who would rather portray as villains anyone who dares suggest what the science really says, is equally clear, to me at least.

2012 will bring the discussion around once again.  Perhaps it will even defend its title of "Controversy of the year"!


P.S.  Honorable mentions in the category "Controversy of the Year" get their own post later today!